Variable loudness alarm mechanism



y 1966 c. B. MARBLE 3,251,182

VARIABLE LOUDNESS ALARM MECHANISM Filed March 24,. 1964 2 Sheets-Sheet 1 fire/7 far (head? A. Mari/e y 1966 c. B. MARBLE 3,251,182

VARIABLE LOUDNESS ALARM MECHANISM Filed March 24, 1964 2 Sheets-Sheet 2 United States Patent 3,251 182 VARIABLE LOUDNESS ALARM MECHANISM Chester B. Marble, Ashland, Mass., assignor to General Electric Company, a corporation of New. York Filed Mar. 24, 1964, Ser. No. 354,228 8 Claims. (Cl. 58-21.12)

This invention relates to electric clocks including a vibrator alarm. More specifically, it relates to a mechanism for varying the loudness of an electromagnetic vibrator alarm.

An electromagnetic vibrator alarm which is incorporated in an electric clock comprises a resilient arm or vibrator, one end of which is secured to the clock assembly in proximity to the motor, and the free end of which is also in proximity to the motor, but is spaced from the motor. A portion of the motor flux passes through the vibrator such that during periods of maximumflux the free end of the vibrator is attracted to and engages the motor, thereby sounding the alarm. The loudness of the alarm can be varied by varying the amplitude of oscillation of the free end of the vibrator, .or in other terms by varying the air gap between the free end of the vibrator and the stationary member which it engages. In prior art alarm intensity controls the amplitude of vibration has been limited by a cam which engages the vibrator or a member connected to the vibrator. Due

to variations in the manufacturing tolerances of these prior art controls, a relatively large portion of the cam movement is used in merely bringing the cam into engagement with the vibrator. The use of a large portion of the cam movement for bringing the cam into engagement with the vibrator may result in insuiiicient or only very limited cam movement remaining for alarm intensity control.

In accordance with this invention, an improved variable loudness alarm mechanism is provided which permits wide variation in the component dimensions and the assembly dimensions of the alarm and variable loudness mechanism, while at the same time providing accurate loudness control of the alarm. Furthermore, the variable loudness mechanism constructed in accordance with this invention not only provides accurate loudness control, but this control is of the vernier type, whereby easy adjustments can be. made in the alarm loudness.

It is an object of this invention to provide a variable loudness alarm mechanism which provides accurate loudness control in spite of wide tolerances of the dimensions and materials of the clock and the variable loudness alarm mechanism assemblies.

It is another object of this invention to provide a variable loudness alarm mechanism which permits accurate vernier type control of the loudness of the alarm, whi'le'at the same time permitting dimensional variations 7 in the components and their assembly.

These objects are accomplished in accordance with this invention, in one form thereof, by employing a vibrator, spring, cam and lever mounted on the electric clock assembly in a predetermined spaced relationship. A first arm of the spring, which has'two arms, is positioned so that it may be brought into engagement with the vibrator near its free end. In response to movement of the second arm of the spring by the lever,- the first arm is brought into engagement with and then displaces the free end of the vibrator. The loudness of the alarm is adjusted by varying the position of the vibrator in response to movement of the spring arms and the lever by a cam engaging the lever. The cam, lever, and spring arrangement provides a large mechanical ratio for multiplying the cam displacement to bring the first arm of the spring into engagement with the vibrator. After engagement of the first arm of the spring with the vibrator,

3,251,182 Patented May 17, 1966 deflection of the spring results in a vernier type adjust- I ment of the vibrator position.

Other objects and further details of that which is believed to be .novel and the invention will be clear from the following description and claims taken with the accompanying drawing wherein:

FIG. 1 is a rear perspective view of an electric clock incorporating the variable loudness alarm mechanism contemplated by this invention;

FIG. 2 is a top view of the electric clock with the cover removed;

FIG. 3 is a rear view of the clock with the cover removed and portions broken away, and with thevariable loudness alarm mechanism in an operating position;

FIG. 4 is similar to FIG. 3, butwith the variable loudness alarm mechanism in an inoperative position;

FIG. 5 is an exploded view of the principal components of the variable loudness alarm mechanism and the vibrator of the alarm;

FIG. 6 is an enlarged view of the adjustment cam; and

FIG. 7 is a displacement chart for the variable loudness alarm mechanism.

The controls of an electric clock incorporating a pre ferred embodiment of the variable loudness alarm mechanism of this invention can best be seen by making ref: erence to FIG. 1. Shown protruding through the rear of the casing 10 is a time set knob 11, an alarm set knob 12, and an alarm on-ofi' lever 13. Also protruding from the rear of the housing is a coin slot control knob 14 which is used to adjust the variable loudness alarm mechanism of this invention. By reference to FIGS. 2 through 5 it will be seen that the clock comprises a motor 15, a gear train 16 mounted between front plate 17 and back plate 18, and indicating hands 19. In a preferred embodiment of an electric clock including the variable loudness alarm mechanism, the vibrator 20 is formed from a piece of steel. The vibrator includes a major portion 22 and a flange 21 which is perpendicular to the major portion. The flange is welded to the back plate 18 of the clock. The free end 23 of the vibrator which engages a portion of the motor stator or a stationary member 25 to sound the alarm, is generally parallel to but offset from the major portion 22 of the vibrator. The free end 23 of the vibrator includes a bent tab 24 which is provided for engagement with the on-oif lever 13.

The vibrator is mounted parallel to and in close proximity with the top portion or yoke of the motor stator 25. A portion of the alternating leakage flux which would normally pass through the air is shunted through the vibrator 20 thereby causing periodic attraction of the free end 23 of the vibrator to the motor stator 25. Periodic engagement of the free end 23 of the vibrator and motor stator 25 will cause sounding of the alarm.

As is well-known in the art, it is possible to vary the loudness of an electromagnetic vibrator alarm by varying the air gap between the vibrator and the stationary member which it strikes. This invention is related to an improved mechanism for varying the air gap, and simultaneously the stiffness of the vibrator, and thereby varying the loudness of the alarm. The improved variable loudness mechanism of this invention is best shown in FIG. 5. A lever 26 is pivotally supported by pin 27. Rotation of a cam 28 in an aperture 29 in the lever causes rotation of the lever about pin 27. The free end of the lever includes a spring-engaging means 30 which may be a tab 31 bent at right angles to the lever with a hole 32 therein. A sear spring 33, the convolute section 34 of which is placed over stud 33a, is provided for adjusting the position and stifiness of vibrator 20, in response to movement of lever 26. The sear spring 33 p has arms of unequal length. The shorter arm 35 is connected to the spring-engaging means 30 of the lever, while portion 37 of the longer arm 36 is positioned to engage the top surface of the vibrator 20.

Rotation of the cam 28 in a clockwise direction causes the lever 26' to be pivoted in a clockwise direction, thereby rotating the short arm 35 of sear spring 33 in a counterclockwise direction. Counterclockwise rotation of the spring 33 brings portion 37 of the longer arm 36 of the spring into engagement with the top surface of the vibrator 20.

Until the portion 37 of the spring 33 engages the vibrator, the lever system comprising the cam 28, the lever 26, and the sear spring 33 has a large mechanical ratio, such as 18 to 1. This large ratio results from positioning the aperture 29 closer to pin 27 than is the springengaging means 30, and by making the spring arm 35 shorter than the spring arm 36. Slight rotation of the cam 28 will effect a relatively large movement of the portion 37 of the longer spring arm 36. Even though the mechanical tolerances of the dimensions and positions of the alarm mechanism components are large, it is possible to compensate for these large tolerances by bringing the portion 37 of the longer spring arm 36 into contact with the vibrator 20 by a very slight rotation of the control knob 14.

After the portion 37 of the spring contacts the vibrator 20, the mechanical ratio of the lever system becomes smaller due to the tensioning of the spring 33. Rotation of cam 28 causes gradual deflection of the spring, and at the same, time portion 37 of the spring applies a force to the free end 23 of the vibrator, thereby increasingthe stiffness of the vibrator and reducing the air gap between the free end 23 of the vibrator and the stationary member 25. The gradual deflection of the spring 33, and the gradual application of the force to the top of the vibrator by portion 37 of the spring due to rotation of the cam 28, results in a vernier type action wherein easy adjustengages the vibrator 20, the load on the lever system is' Therefore, the spring 33 is not tensioned or negligible. deflected and a large mechanical ratio results, whereby a slight rotation of the cam will bring the spring into engagement with thevibrator 20. This action of the lever system is indicated by the steeply sloped portion 38 of the displacement curve shown in the displacement chart. After the portion 37 of the spring 33 engages the vibrator 20, the spring 33 is tensioned due to the force needed to deflect the vibrator. The deflection of the spring results in a considerable reduction of the mechanical ratio of the lever system, thereby providing vernier type control of the alarm loudness. This vernier type control is indicated by the gradually sloped portion 39 of the displacement curve.

While a preferred embodiment of the invention has been shown, various other modifications and embodiments of the invention will be apparent to those skilled in the art, and it is intended to cover by the appended claims all said modifications falling within the scope thereof.

What I claim is:

1. A variable loudness alarm mechanism for use with an electric clock comprising:

(a) a vibrator for sounding an alarm,

(b) pivot means spaced from said vibrator,

(c) a spring having a first arm, a second arm, and a (d) a pivoted lever engaging said second arm,

(e) a cam engaging said lever to effect movement of said lever and said spring to vary the loudness of the alarm.

2. A variable loudness alarm mechanism for use with an electric clock comprising:

(a) a vibrator for sounding an alarm,

(b) pivot means spaced from said vibrator,

(c) a spring having a first arm, a second arm, and a pivot portion between said arms, the pivot portion of said spring being mounted on said pivot means, and said first arm being arranged to engage said vibrator for urging said vibrator in one direction,

(d) a pivoted lever engaging said second arm, said lever having an aperture therein,

(e) a cam engaging a wall of said aperture to effect movement of said lever and said spring to vary the loudness of the alarm.

3. The variable loudness alarm mechanism defined in claim 2 wherein said first arm is longer than said second arm.

t. A variable loudness alarm mechanism for use with an electric clock comprising:

(a) a vibrator for sounding an alarm,

('b) pivot means spaced from said vibrator,

(c) a spring having a longer arm, a shorter arm, and

a pivot portion between said arms, the pivot portion of said spring being mounted on said pivot means,

and said longer arm being arranged to engage said' vibrator for urging said vibrator in one direction,

(d) 'a pivoted lever engaging said shorter arm, said lever having an aperture therein between the pivot point of said lever and the portion of said lever which engages said shorter arm of said spring,

(e) a cam engaging a wall of said aperture to effect movement of said lever and said spring to vary the loudness of the alarm.

5. The variable loudness alarm mechanism defined in claim 4 wherein said aperture has a major dimension and a minor dimension, the major dimension extending generally in the direction of a line between the pivot point of said lever and the portion of said lever which engages said shorter arm of said spring.

6. The variable loudness alarm mechanism defined in claim 4 wherein the cam is heart-shaped.

7. The variable loudness alarm mechanism defined in claim 4 wherein said aperture is generally rectangular, the longer dimension of said aperture extending generally in the direction of a line between the pivot point of said lever and the portion of said lever which engages said shorter arm of said spring.

8. A variable loudness alarm mechanism for use with an electric clock comprising:

(a) a vibrator for sounding an alarm,

(b) pivot means spaced from said vibrator,

(c) a spring having a longer arm, a shorter arm, and

a pivot portion between said arms, the pivot portion of said spring being mounted on said pivot means, and said longer arm being arranged to engage said vibrator for urging said vibrator in one direction,

((1) a pivoted lever engaging said shorter arm, said lever having a generally rectangular aperture therein closer to the pivot point of said lever than to v the portion of said lever which engages said shorter arm of said spring, the longer dimension of said aperture extending generally in the direction of a line between the pivot point of said lever and the portion of said lever which engages said shorter arm of said spring,

(e) a cam engaging a wall of said aperture to elfect movement of said lever, whereby the cam displacement effected by an initial predetermined rotation of said cam is multiplied tocause substantial dis- 3,251,182 5 6 placement of said longer arm into engagement with References Cited by the Examiner said vibrator, and a subsequent similar predeter- UNITED STATES PATENTS nnned rotation of said cam causes the deflection 2,506,379 5/1950 Muchow and tensionmg of said spring and therefore a lesser 2 858 029 10/1953 Rabinow 5 g5 5 displacement of said longer arm and said vibrator 5 to give a Vernier control of the variation in the LOUIS J-CAPOZLPrima'ZV Examinerloudness of the alarm. LEO SMILOW, G. F. BAKER, Assistant Examiners. 

1. A VARIABLE LOUDNESS ALARM MECHANISM FOR USE WITH AN ELECTRIC CLOCK COMPRISING: (A) A VIBRATOR FOR SOUNDING AN ALARM, (B) PIVOT MEANS SPACED FROM SAID VIBRATOR, (C) A SPRING HAVING A FIRST ARM, A SECOND ARM, AND A PIVOT PORTION BETWEEN SAID ARMS, THE PIVOT PORTION OF SAID SPRING BEING MOUNTED ON SAID PIVOT MEANS, AND SAID FIRST ARM BEING ARRANGED TO ENGAGE SAID VIBRATOR FOR URGING SAID VIBRATOR IN ONE DIRECTION, (D) A PIVOTED LEVER ENGAGING SAID SECOND ARM, (E) A CAM ENGAGING SAID LEVER TO EFFECT MOVEMENT OF SAID LEVER AND SAID SPRING TO VARY THE LOUDNESS OF THE ALARM. 